WECC Data Preparation Manual
for Steady-State and Dynamic Base Case Data
System Review Work Group
Technical Studies Subcommittee
155 North 400 West, Suite 200
Salt Lake City, Utah 84103-1114
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Table of Contents
I.
Introduction ............................................................................................................................. 1
II.
NERC Reliability Standards ........................................................................................................ 1
III.
Definitions ................................................................................................................................ 2
IV.
General Data Requirements and Reporting Procedures ............................................................. 3
Data Requirements ............................................................................................................................ 3
Reporting Procedures ........................................................................................................................ 4
Steady-State Data ........................................................................................................................ 5
Dynamic Data ............................................................................................................................... 5
V.
Steady-State Data Requirements .............................................................................................. 6
AC and DC Buses (MOD-011, R1.1) .................................................................................................... 7
Generation (MOD-011, R1.2) ............................................................................................................. 9
AC Transmission Lines (MOD-011, R1.3, R1.6) ................................................................................ 14
Transformers (MOD-011, R1.5) ....................................................................................................... 17
Fixed Shunt Reactive Elements (MOD-011, R1.6)............................................................................ 22
Controlled Shunt Reactive Devices (MOD-011, R1.6) ...................................................................... 23
Loads (MOD-011, R1.1) .................................................................................................................... 25
DC Transmission Lines (MOD-011, R1.4) ......................................................................................... 28
Area Interchange Schedules (MOD-011, R1.7) ................................................................................ 28
Master Tie-Line File............................................................................. Error! Bookmark not defined.
VI.
Dynamic Data Requirements................................................................................................... 29
Generation Requirements ............................................................................................................... 30
Load Characteristics ......................................................................................................................... 31
Underfrequency Load Shedding (UFLS) ........................................................................................... 31
Undervoltage Load Shedding (UVLS) ............................................................................................... 32
Back-to-Back DC Ties........................................................................................................................ 32
DC Lines, SVC, and D-VAR systems .................................................................................................. 32
VII. Short Circuit Data ................................................................................................................... 33
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VIII. Contingency and Remedial Action Scheme Data ...................................................................... 33
Appendix 1 – Late Data Procedure................................................................................................... 35
Area Coordinator and Staff Responsibilities .................................................................................... 35
Actions to Take................................................................................................................................. 36
Backfitting of Late Data.................................................................................................................... 36
Appendix 2 – Area, Zone and Bus Number Assignments................................................................... 38
Southwest Region ............................................................................................................................ 38
Southern California Region .............................................................................................................. 39
Northern California Region .............................................................................................................. 40
Northwest Region ............................................................................................................................ 41
Canadian Region .............................................................................................................................. 42
Central Region.................................................................................................................................. 42
Eastern Region ................................................................................................................................. 43
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I. Introduction
The North American Electric Reliability Corporation (NERC) is the federally designated Electric
Reliability Organization (ERO) in North America and maintains comprehensive reliability standards that
define requirements for planning and operating the collective Bulk Electric System. The collective Bulk
Electric System must be designed and operated in a coordinated effort in accordance with the NERC
Reliability Standards and the Western Electric Coordinating Council (WECC) Regional Reliability
Standards and Criteria. To help meet these requirements, power system electrical characteristics are
used in steady-state and dynamic stability studies for system evaluation and operations support by the
various members of the WECC community. WECC and its members use steady-state and dynamic data
sets for seasonal Operating Transfer Capability (OTC) studies, WECC’s annual study program, WECC
path rating studies, and regional- and local-area studies.
This WECC Data Preparation Manual (DPM) is to be used by WECC members and any other entities
owning/operating facilities in the Western Interconnection. It covers the submittal and use of both
steady-state and dynamic data. The data requirements are stated in NERC Reliability Standards and
WECC Regional Reliability Standards and Criteria.
The System Review Work Group (SRWG), which reports to the Technical Studies Subcommittee (TSS), is
responsible for maintaining the DPM with oversight from the TSS and Planning Coordination
Committee (PCC). Transmission Owners, Planning Coordinators, Transmission Planners, Generator
Owners, and Resource Planners (i.e., applicable entities) are responsible for submitting steady-state
and dynamic data as required by NERC Reliability Standards and WECC Regional Reliability Standards
and Criteria and in accordance with WECC scheduling requirements and this DPM. Applicable entities
may delegate their data submission activities to a Data Representative; however, the applicable
entities remain responsible. WECC staff is responsible for collecting, archiving, and making available
solved and solvable steady-state and dynamic datasets in the form of WECC base cases for use by
WECC members and others.
Navigating the electronic version of the DPM:
Internal document hyperlinks: Throughout this DPM, there are many references to internal supporting
information. These internal hyperlinks are configured such that when you see a reference that begins
with “See” or “Refer to” followed by text enclosed with double quotes, simply mouse over that text
and you will be given the option of following the link to the supporting section of this document.
II. NERC Reliability Standards
The following NERC Reliability Standards pertain directly to the steady-state and dynamic data
requirements and reporting procedures for use by WECC, Transmission Owners, Planning Coordinators,
Transmission Planners, Generator Owners, and Resource Planners. It is required that these NERC
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Reliability Standards and WECC Steady-State and Dynamic Data Criterion be followed when submitting
data for the purpose of compiling WECC base cases.
The DPM is intended to help in the implementation of and support for the following NERC Reliability
Standards and WECC Steady-State Criterion:

MOD-010: Steady-State Data for Modeling and Simulation of the Interconnected Transmission
System;

MOD-011: Steady-State Data Requirements and Reporting Procedures;

MOD-012: Dynamic Data for Modeling and Simulation of the Interconnected Transmission
System;

MOD-013: Maintenance and Distribution of Dynamic Data Requirements and Reporting
Procedures;

FAC-008-3: Establish and Communicate Facility Ratings; and

WECC Steady-State and Dynamic Data Criterion.
III. Definitions
Area: An Area is a subset of the Western Interconnection System Model composed of generators and
connected contiguous elements to assist in the coordinated development of a WECC Base Case. The
data for the defined Areas with coordinated Area schedules is submitted to WECC by the Area
Coordinators. The defined Areas are listed in “Appendix 2 – Area, Zone and Bus Number Assignments.”
Area Coordinator: The Area Coordinator is an entity to whom the applicable entities have delegated
data collection and coordination activity for a defined Area.
BCCS: Base Case Coordination System is a web-accessible, centralized database that automates base
case building in PSLF and PSS®E formats. It also provides a central location for maintaining base case
information. Refer to the BCCS Data Submitter's Guide for a detailed guide to using the BCCS.
Data Representative: An entity delegated the data submission activities of Generator Owner(s),
Transmission Owner(s), Transmission Planner(s) and/or Resource Planner(s) to submit steady-state and
dynamic data according to the WECC DPM to Area Coordinators or Sub-Area Coordinators. An example
of a Data Representative may be the Transmission Planning entity of the Transmission Planning Area in
which a Generator Owner and/or Transmission Owner’s facilities are located. This term is included for
convenience in reference only. An owner may submit data with or without a Data Representative.
Generation Netting: The representation of a generator(s) through the modeling a load element with
the real and reactive power requirements set to the net of generation and load. Alternatively,
Generation Netting may be the representation of a generator(s) using a load element with a negative
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Real Power demand setting. Generation Netting may be used only in Dynamic simulations by including
the Generator element in the Netting section of the Positive Sequence Load Flow (PSLF) ‘dyd’ file for a
given WECC Base Case.
Master Dynamics File (MDF): File in PSLF ‘dyd’ format containing dynamic data for use in the
compilation of all WECC Base Cases.
Planned Facilities: Planned facilities that have not yet met their in-service date at the time data is
submitted for inclusion in a base case. See the “General Data Requirements and Reporting Procedures”
section.
PSLF: GE’s Positive Sequence Load Flow software tool for electrical transmission analysis.
PSS®E: Siemens PTI’s Power System Simulator for Engineering software tool for electrical transmission
analysis.
Sub-Area Coordinator: A Sub-Area Coordinator is an entity that represents a subset of the data
collection and coordination activity within an Area. The sub area data is submitted to an Area
Coordinator.
WECC Base Cases: A set of solved and solvable steady-state and dynamic data representing a specific
operating scenario of the Western Interconnection compiled by WECC staff in cooperation with WECC
members.
WECC staff: Employees of WECC who participate in the coordination of steady-state and dynamic data
for use in creating WECC Base Cases.
IV. General Data Requirements and Reporting Procedures
Data Requirements
Power system modeling data requirements are stated generally in the NERC Reliability Standards and
WECC Regional Reliability Standards and Criteria.
Accuracy of the data utilized in the steady-state and dynamic data sets is imperative as it must support
informed decisions regarding power system expansion and operation. System response and
parameters measured in simulating system operation must be comparable to measurements of the
actual power system under the same conditions. Study results either overly optimistic or too
pessimistic could lead to uninformed decisions regarding the design or operation of the power system
and potentially adversely affect reliable operation.
Data representation should be in sufficient detail to adequately evaluate all system conditions of load,
generation and interchange as well as steady-state and dynamic conditions of the power system. As a
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guide, the level of detail should be at least that used by the member systems in conducting their own
internal studies for the purpose of supporting their own system expansion and operating decisions.
Planned Facilities shall be included in submitted data if:

the facilities are expected be in-service on the scheduled base case posting date;

the facilities are expected to be in-service in the month and year represented in the case; or

the facilities are required to support proposed generation facilities that are modeled in-service
in the case.
All data must be the best available data. Dynamic data resulting from equipment testing should be
provided if it is available. If test data is not available then design data should be provided. If design
data is not available then generic Dynamic data should be provided. In-service equipment should be
supported by test data while far-term planned equipment may only have generic Dynamic data
available.
Reporting Procedures
The required data is requested to be supplied periodically throughout the calendar year on a schedule
that supports all the various study activities: seasonal OTC studies, WECC's annual study program, path
rating studies and regional and local area studies. Each fall, WECC issues a 10-Year Base Case Data
Compilation Schedule (DCS) showing schedules for each case that is to be submitted during the year.
Separate data request letters are then issued throughout the year in a scheduled sequence that
supports the DCS. The data request letters provide a detailed description of each case to be submitted.
All those who contribute to the data submittal effort (Area Coordinators, Transmission Owners,
Transmission Planners, and Generator Owners and Resource Planners) are required to submit the
requested data in accordance with the stated schedule. A Late Data Procedure (see “Appendix 1 – Late
Data Procedure”) is used when necessary to help preserve the original schedules stated in the DCS. It
also allows tracking of late data and keeping TSS and PCC informed when the schedule is about to be
compromised.
Data owners are responsible for validating and verifying the accuracy of their data maintained in the
BCCS and contained in the Master Dynamics File (MDF) for any of their solely- or jointly-owned
facilities prior to data submittal. With exemption to dynamics data, data owners and planners are
responsible for submitting the required data to WECC via the BCCS system. Area Coordinators are then
responsible for reviewing the submitted data for errors. Email to WECC to request password access to
the BCCS and to send updates to dynamics data.
Data submittals to WECC may only be done in BCCS project file (prj) format in the version that is
currently approved by WECC for production use. Submitted files must also follow the file structures
defined in the BCCS Data Submitter's Guide. WECC will compile the data received into a solved and
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solvable case that initializes correctly with the latest Dynamic data updates included in the Master
Dynamics File. The base case along with the updated Dynamic data file and all associated materials
(case details associated with each Area) are posted on the WECC website for review and comment.
WECC will send an email to its members announcing the posting and requesting a second review.
WECC will again incorporate the submitted changes from the second review into the case and post the
approved case along with the approved updated Dynamic data file and associated materials to the
WECC website. WECC will send an email to WECC members announcing the posting of the approved
case.
Flexibility in due dates can be granted by WECC staff due to BCCS technical difficulties. Contact WECC
via the email prior to due dates if technical difficulties occur so alternate submittal methods can be
arranged.
Steady-State Data
Power system electrical characteristics in the form of Steady-State positive-sequence data are required
in accordance with NERC Standards MOD-010 and MOD-011 and are to be submitted in accordance
with established requirements (see “
Steady-State Data Requirements”) and the WECC Steady-State and Dynamic Data Criterion
Dynamic Data
Power system electrical characteristics in the form of Dynamic data are required in accordance with
NERC Standards MOD-012 and MOD-013 and are to be submitted in accordance with established
requirements (see “
Dynamic Data Requirements”) and the WECC Steady-State and Dynamic Data Criterion.
Dynamic data is submitted as soon as any new data becomes available. Dynamic data may become
available outside the scheduled case building process as a result of individual entity equipment testing
programs such as the generator testing program. Dynamic data for equipment such as generators,
motors, frequency or voltage load shedding models, load representation models, etc., should be
submitted to WECC as soon as the new data is available.
Dynamic data for the entire Western Interconnection is kept in the MDF. It is critical that this file be
maintained and updated as soon as new or updated Dynamic data is available. Every base-case-data
request letter includes an additional request for updated Dynamic data. This includes Dynamic data for
generators and associated power plant models, motors, Underfrequency Load Shedding and
Undervoltage Load Shedding models, load representation models, DC lines, Static Var Compensators
(SVC), and any other Dynamic equipment modeled in the WECC Base Case.
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Facility owners are responsible to test and validate Dynamic data for any of their solely- or jointlyowned Dynamic equipment to be modeled in WECC cases. Facility owners shall provide test reports,
validation reports, and Dynamic model data to their Transmission Planners. It is advisable for Facility
Owners to request acknowledgement of receipt of the data for compliance documentation purposes.
Dynamic data for new generators and updates for existing generators are submitted via the WECC
Generating Unit Model Validation Policy. The WECC Generating Unit Model Validation Policy includes
the roles and responsibilities of the Generator Owner, the Transmission Planner, and WECC .
The most recent version of the MDF is available in the current year of the Base Case Files, in the PSLF
library located here: Master Dynamics File.
Note: The MDF is in PSLF format. Dynamic data for PSS®E is created using conversion software
developed by Siemens PTI.
V. Steady-State Data Requirements
To establish consistent system models to be used in the system analysis of the reliability of the
interconnected transmission system; Transmission Owners, Transmission Planners, Generator Owners,
and Resource Planners shall provide steady-state data to WECC according to the requirements listed
herein. To provide consistency in data submittals and help avoid potential solution problems, the
guidelines below shall be followed to the maximum extent possible. However, WECC recognizes
deviations from the guidelines may occasionally be needed. For these situations, submitters are
requested to provide the SRWG and MVWG with the rationale for exceptions. The Interconnectionwide requirements shall include the following steady-state data requirements:

With the exception of collector-based generation such as wind and solar all Bulk Electric System
elements, as presently defined by NERC, within the Western Interconnection shall be
represented in WECC Base Cases without equivalencing.

Non-Bulk Electric System elements may also be included in WECC Base Cases and must follow
the same data submittal requirements as those for Bulk Electric System elements. Any
equivalencing of non-Bulk Electric System elements shall be modeled to yield almost identical
performance of a full representation in both static and dynamic analysis.

Non-Bulk Electric System elements shall be included if it has been determined that they have
significant interaction with Bulk Electric System elements. Non-Bulk Electric System elements
that may have a significant interaction with Bulk Electric System elements may exhibit one or
more of the following characteristics:
o Facilities that are operated at or above 50 kV
o Facilities that are operated in parallel with BES elements
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o Facilities with connected individual generation resources >=10 MVA or aggregate
generation resources >=20MVA
o Facilities with connected reactive resources >=10 MVAR

Non-Bulk Electric Local Networks and radial systems that feed only load or parallel/looped
systems that are normally operated in a radial configuration would generally be excluded from
modeling.

Steady-state power flow data submitted as described in the data request letter shall represent
the existing Bulk Electric System elements plus planned transmission and generation facilities as
deemed appropriate by the data submitting entity.

Paths defined in the WECC Path Rating Catalog shall be modeled to include all elements
consistent with the path definition.

All data submittals shall conform to and meet the data requirements of the latest WECC
approved version of the BCCS.

Data fields that are strings shall not contain commas, single quotes, or double quotes.

Key element identifiers (e.g., number, name, base voltage, ID) that indicate an element
representing the same equipment shall be consistent between base cases.
o Devices with alpha characters shall consistently use either uppercase or lowercase IDs.
o Bus names with alpha characters shall consistently be either uppercase or lowercase.

Uniqueness shall not depend on names and IDs being case sensitive.

The required data is listed below in the tables of data requirements. Data fields listed in this
DPM are all required and any description for the field shall be followed.

Bus naming guideline: Although the criterion for bus names is that ‘Bus names shall be unique
within the same Base Voltage class,’ it is intended that, ideally, bus names should be the same
for all equipment located in the same vicinity. For example, two substations that are in different
areas could both be named “Midway.” Names could be set to “MIDWAY” at one location, and
to “MDWAY” at the other. The SRWG strongly suggests that naming of new buses added to the
model adhere to the ideal guideline. It recommends, but it is not mandatory, to eliminate
spaces in bus names and substitute underscore characters instead. It is the responsibility of the
party adding bus information to assure there is no name duplication.
AC and DC Buses (MOD-011, R1.1)
General Requirements:
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1. Buses usually represent all of the equipment in a substation that is at the same voltage level and is
connected together. If desired, multiple bus sections can be represented by separate buses
connected by AC Transmission Line models that can be opened or closed as needed. Buses may
also represent a node on a transmission line such as a tapping point or change in ownership.
2. Location of the bus will be identified by the combination of Area, Zone, and/or Owner fields.
Optionally, the latitude and longitude fields can be submitted using decimal degrees with data
entered not to exceed five decimal places.
Table 1: Data Requirements (Buses)
Field
Description
Requirements
Number
Bus number
B1. Refer to “Appendix 2 – Area, Zone and Bus Number
Assignments” for designated ranges of Bus numbers.
B2. WECC staff shall provide DC Bus numbers.
Name
Bus name
 Alphanumeric string
containing 1 to 12
characters
 At least one non-numeric
character
B3. Bus names shall be unique within the same Base
Voltage class.
Base
Voltage
Nominal voltage class of Bus (kV)
Bus Type
AC Bus type {0,1,2,-2}
 0 = swing bus (voltage
magnitude and phase fixed)
 1 = load bus (unconstrained
voltage angle and magnitude)
 2 = generator bus (voltage
control [terminal or remote]
within generator limits)
 2 = generator bus with unlimited
reactive power limits
Other bus types may be used to
indicate OFF status.
Bus type -4 and smaller is the
accepted convention for deleted
buses.
DC Bus type {1,2}
 1 = for a rectifier
 2 = for an inverter
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Field
Description
Requirements
DC
System
Number
DC system number
(not required for AC Bus)
B4. WECC staff shall assign a DC system number for each
DC system prior to model submission.
Scheduled
Voltage
Scheduled voltage (pu)
 5 decimals
 Default: 1.00000
B5. If the Bus is regulated by a generator or other device,
the scheduled voltage shall be specified in per unit
with respect to the Base Voltage of the Bus.
B6. If the Bus is not regulated, the scheduled voltage is
optional and for information purposes only.
Area
Area in which Bus is located
B7.
Zone
Zone in which Bus is located
B8. Refer to “Appendix 2 – Area, Zone and Bus Number
Assignments” for designated ranges of Zones used by
Area.
Owner
Owner Number
B9. Owner Number shall be the Transmission Owner,
Generator Owner, or reporting entity, by written
agreement.
B10. WECC staff shall assign Owner Number to required
entities.
Refer to “Appendix 2 – Area, Zone and Bus Number
Assignments” for designated Area.
Generation (MOD-011, R1.2)
General Requirements:
1. Modeling of generators in WECC Base Cases shall comply with WR9 of the WECC Steady-State and
Dynamic Data Criterion.
2. Steady-state and dynamic generator data shall be consistent per WR10 of the WECC Steady-State
and Dynamic Data Criterion.
3. Synchronous motors 10 MVA and larger shall be modeled as individual machines, using a generator
model with negative Real Power output and constant Q.
4. The netting of small generating units with single capacity greater than or equal to 10 MVA or
aggregate capacity greater than or equal to 20 MVA may not be modeled as a negative load.
Generators modeled as negative load shall have an assigned load ID of ‘NT’ and have their ‘nonconforming load FLAG’ set appropriately.
5. Induction motors shall be modeled as a load with the intent of using an induction motor model
(MOTORW).
6. Synchronous condensers shall be modeled individually using a generator model.
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7. Generator step-up transformers shall be modeled explicitly; therefore, they shall not be modeled
using the internal generator step-up transformer feature of a generator model. All related
parameters shall be set to the default values. See “Data Requirements (Transformers).”
8. Station service loads (ID = ‘SS’) shall be represented explicitly as separate loads on the generator
bus. See “Data Requirements (Loads).”
9. Wind and photovoltaic projects shall be represented through an equivalent generator(s),
equivalent low-voltage to intermediate-voltage transformer, equivalent collector system, and
substation transformer between the collector system and the transmission bus. See the WECC
Wind Power Plant Power Flow Modeling Guide and PV Plant Power Flow Modeling Guide.
10. Large industrial sites may include imbedded generation. Industrial generators 10 MVA and larger
shall be represented in power flow instead of netting with the total load. If a generator is
connected to the low side of the bulk-power-delivery transformer, then the transformer must be
represented in the power flow and the generator and load must be connected to the low-voltage
side of the transformer.
11. Generator maximum Real Power Pmax in power flow must be consistent with the turbine
capabilities defined in the Master Dynamics File.
Table 2: Data Requirements (Generation)
Field
Description
Bus
Numbers
Number of the Bus to which the
generator is attached.
Requirements
Measure
 See “Data Requirements
(Buses)”
Unit ID
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Two -character Generator
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Field
Description
Requirements
Status
Generator status
G1.
Out-of-service units shall have
status set to zero.
G2.
Retired units shall be deleted
rather than having status set
to zero.
G3.
Pgen shall be at or within the
unit Pmax and Pmin
parameters for units that are
in-service.
If Status = 1:
Pmin ≤ Pgen
≤ Pmax
G4.
Pmax shall reflect the
maximum Real Power output
of the unit, also known as
‘gross’ capability.
Pmax ≤
Governor
Max
G5.
Pmax shall not be greater than
the maximum capability of the
unit represented by the
governor model.
G6.
Pmin shall reflect the
minimum Real Power output
of the unit.
G7.
Pmin shall be less than or
equal to Pmax.
 1 = in-service
 0 = out-of-service
Pgen
Real Power output (gross MW)
Qgen
Reactive power output (MVAr)
Pmax
Maximum Real Power output
(MW)
Pmin
Minimum Real Power output
(MW)
Measure
Pmin ≤ Pmax
Qmax
Maximum reactive power output
(MVAr)
G8.
Qmax shall reflect the
appropriate maximum reactive
power output of the unit.
Qmin
Minimum reactive power output
(MVAr)
G9.
Qmin shall reflect the
appropriate minimum reactive
power output of the unit.
Qmin ≤ Qmax
G10. Qmin shall be less than or
equal to Qmax.
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Description
Q Alloc
Factor
Reactive power regulating
assignment factor
12
Requirements
Measure
 0.0 – 1.0
 > 0.0 for AVR control
 0.0 for constant PF control
or gen ST=0
Q Table Flag
Reactive capability curve flag
 0 = do not use capability
curve
G11. Q-Table data used for internal
studies shall be included in
WECC Base Case submittals.
 1 = use capability curve if it
exists
Base load
Flag
Base load flag
 0 = non-base load unit
(responds to low frequency
with additional mechanical
power)
 1 = base load unit (cannot
respond to low frequency
with additional mechanical
power)
 2 = base load unit (cannot
respond to low and high
frequency with mechanical
power)
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Field
Description





Turbine
Type













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Requirements
0 = unknown
1 = non-reheat steam
2 = reheat steam
3 = steam cross-compound
4 = steam in combined cycle
(separate shaft)
5 = hydro
6 = diesel non turbo
charged
7 = diesel turbo charged
11 = industrial GT (single
shaft)
12 = aero derivative GT
13 = single shaft combined
cycle
14 = Synchronous
condenser (no turbine)
21 = type 1 wind turbine
22 = type 2 wind turbine
23 = type 3 wind turbine
24 = type 4 wind turbine
31 = photovoltaic
40 = DC tie (generators
representing DC ties)
Reg Bus
Bus with voltage controlled by
this Generator
Vsched
Generator scheduled voltage
(pu)
Area
Area in which generator is
located
G13. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
Area.
Zone
Zone in which generator is
located
G14. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
ranges of Zones used by Area
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E
L E C T R I C I T Y
G12. Regulation of a remote Bus
that does not represent actual
system operation shall be
avoided.
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Field
Description
Requirements
Measure
Base MVA
Generator base (MVA)
G15. Unit Base MVA shall be equal
to the MVA Base parameter of
the unit’s Dynamic machine
model.
Base MVA =
Machine Base
Owner
Owner Number
G16. Owner Number shall be the
Generator Owner.
 Up to 8 owners allowed
G17. WECC staff shall assign Owner
Number to required entities.
G tap
Tap ratio of generator step up
transformer
G18. G tap shall be set to 1.
G tap = 1
R TR
Resistance of generator step up
transformer
G19. R TR shall be set to 0.
R TR = 0
XTR
Reactance of generator step up
transformer
G20. X TR shall be set to 0.
X TR = 0
R Subtransient
Sub-transient resistance of
generator
X Subtransient
Sub-transient reactance of
generator
G21. X Sub-transient shall be equal
to the sub-transient reactance
represented in the unit
Dynamic machine model.
X Subtransient =
Xdpp (or
Ldpp)
AC Transmission Lines (MOD-011, R1.3, R1.6)
General Requirements:
1. Series-connected reactive devices modeled in AC Transmission Lines shall be explicitly modeled.
2. When bus ties are necessary, the impedance should be R = 0.0 pu and X = 0.00029 pu, or less. No
value of charging (G or B) is allowed on lines having less than the jumper threshold impedance. Do
not make a closed loop (ring-bus representation) with ties that are less than the threshold
impedance. In addition, do not use bus ties to connect different areas.
3. Normal and emergency thermal rating fields for summer, winter, spring, and fall shall be submitted
and stored in the BCCS in rating profiles. Refer to the for formatting and structure requirements
for these files.
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4. Line connected transformers shall not be modeled using the internal line connected transformer
feature of a transmission line model; all related parameters shall be set to the default values. See
“Data Requirements (Transformers).”
5. Data for AC lines will consider the length of the line when calculating line parameters. For example,
long lines will be modeled with impedances adjusted to account for the uniform distribution of the
series impedance and shunt admittance along the length of the line.
6. PSS®E base case data includes three facility ratings for transmission lines. Ratings 1 and 2 are used
for seasonal normal and emergency ratings in the season of the case. Rating 3 is used for various
other purposes. WECC staff will load the appropriate seasonal ratings into ratings 1 and 2 when
creating PSS®E cases in the BCCS.
Table 3: Data Requirements (AC Transmission)
Field
Description
FROM Bus
Number
Number of the bus to which the
FROM end of the transmission line
section is attached.
Requirements
Measure
 See “Data Requirements (Buses)”
TO Bus
Number
Number of the bus to which the TO
end of the transmission line section
is attached.
 See “Data Requirements (Buses)”
Circuit ID
Circuit identifier
 Two-character circuit identifier
X1. AC Transmission Line modeling
equivalent circuits shall have Circuit
ID set to ‘99’ or ‘EQ.’
Section
Number
Section number (1-9 in ascending
order beginning at FROM end)
X2. AC Transmission Line with multiple
sections shall number the sections
consecutively starting with ‘1.’
Status
Branch status
X3. AC Transmission Line shall have the
anticipated status of the line in the
case.
 0 = out-of-service
 1 = in-service
 2 = bypass
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Field
Description
Requirements
R
Branch section positive sequence
resistance
X4. Resistance used for modeling an AC
Transmission Line shall conform to
the modeling practices as deemed
appropriate by the Transmission
Owner.
X
Branch section positive sequence
reactance
X5. Reactance used for modeling an AC
Transmission Line shall conform to
the modeling practices as deemed
appropriate by the Transmission
Owner.
B
Branch section positive sequence
susceptance
X6. Susceptance used for modeling an
AC Transmission Line shall conform
to the modeling practices as
deemed appropriate by the
Transmission Owner.
Rating
MVA 1
Summer Normal Branch Rating
(MVA)
X7. Line rating required
Rating MVA 1
>0
Rating
MVA 2
Summer Emergency Branch Rating
(MVA)
X8. Line rating required
Rating MVA 2
>0
Rating
MVA 3
Winter Normal Branch Rating (MVA)
Rating
MVA 4
Winter Emergency Branch Rating
(MVA)
Rating
MVA 5
Fall Normal Branch Rating (MVA)
Rating
MVA 6
Fall Emergency Branch Rating (MVA)
Rating
MVA 7
Spring Normal Branch Rating (MVA)
Rating
MVA 8
Spring Emergency Branch Rating
(MVA)
From
Loss factor (0.0 - 1.0) used to assign
losses
Loss
Assign.
Measure
 1.0 = 100% loss assigned to FROM
end of AC Transmission Line
 0.0 = 100% loss assigned to “TO”
end of AC Transmission Line
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Field
Description
Requirements
Area
AC Transmission Line Area location
X9. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated Area
Zone
Transmission Line Zone location
X10. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated ranges of Zones used by
Area
Ohms
Ohmic data flag
Measure
 0 = impedances in pu
 1 = impedances in ohms
Owner
Owner Number (1 through 8)
X11. Owner Number shall be the
Transmission Owner of transmission
facility and Generator Owner of
generation facility.
X12. WECC staff shall assign Owner
Number to required entities.
Transformers (MOD-011, R1.5)
General Requirements
1. Transformers with no Tap Changing Under Load (TCUL) or phase-shifting capability shall have the
Tap Control Type field set to ‘1’ and shall not have TCUL or phase-shifting data included in the
model. Conversion from the latest approved version of PSLF to other widely used programs may
create model discrepancies with partial TCUL or phase-shifting data.
2. Transformer data can be entered on either the transformer base (transformer winding MVA base
and winding voltage base) or the system model base (100 MVA and system nominal voltage base).
Impedance values and tap position values shall use a consistent unit base value for a given
transformer.
3. Normal and Emergency thermal rating fields for summer, winter, spring, and fall shall be submitted
and stored in the BCCS in rating profiles all Transformer models. See Appendix 3 for formatting and
structure requirements for these files.
4. PSS®E cases use ratings 1 and 2 for seasonal normal and emergency ratings in the season of the
case. If directed by the Area Coordinator, WECC staff will load the appropriate seasonal ratings into
ratings 1 and 2 when creating PSS®E cases in the BCCS.
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Table 4: Data Requirements (Transformers)
Field
Description
FROM Bus
Number
Number of the bus to which the
FROM end of the transformer is
attached.
Requirements
Measure
 See “Data Requirements (Buses)”
TO Bus
Number
Number of the bus to which the
“TO” end of the transformer is
attached.
 See “Data Requirements (Buses)”
Circuit ID
Circuit identifier
 Two-character circuit identifier
Status
Transformer Status
 0 = out-of-service
T1. Transformer modeling equivalent
circuits shall have Circuit ID set to
‘99’ or ‘EQ.’
T2. Transformers shall have the
anticipated status of the
transformer in the case.
 1 = in-service
 2 = secondary open
 3 = tertiary open
 4 = primary open
Tap Control
Type
Transformer type code
 1 or 11 = Fixed
 2 or 12 = TCUL
 4 or 14 = Phase-Shifting
Regulated
Bus Number
Number of Bus with voltage
regulated or “TO” bus number for
phase-regulated transformer
Impedance
Table
Number
Impedance correction table
number
Tert Bus
Number
Tertiary winding Bus number
3wpt Bus
Number
Internal ‘3-winding point’ Bus
number
T3.
Regulation of a remote bus that
does not represent actual system
operation shall be avoided.
 See “Data Requirements (Buses)”
 See “Data Requirements (Buses)”
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Field
Description
Requirements
Area
Area in which Transformer is
located
T4. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated Area.
Zone
Zone in which Transformer is
located
T5. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated ranges of Zones used
by Area.
FROM-TO
Base MVA
Transformer MVA base (prim. to
sec. for 3-wndg)
FROM-Tert
Base MVA
MVA base - prim. to tertiary for 3wndg
TO-Tert Base
MVA
MVA base - tertiary. to sec. for 3wndg
R FROM-TO
Resistance primary to secondary
X FROM-TO
Reactance primary to secondary
R FROM-Tert
Resistance primary to tertiary
X FROM-Tert
Reactance primary to tertiary
R TO-Tert
Resistance secondary to tertiary
X TO-Tert
Reactance secondary to tertiary
FROM
Winding
Nom Volt
Primary winding nominal voltage
(kV)
TO Winding
Nom Volt
Secondary winding nominal voltage
(kV)
Tert Winding
Nom Volt
Tertiary winding nominal voltage
(kV)
FROM Fixed
Tap
Primary winding fixed tap position
(pu)
TO Fixed Tap
Secondary winding fixed tap
position (pu)
Tert Fixed
Tap
Tertiary winding fixed tap position
(pu)
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Field
Description
Requirements
Measure
Variable V
Tap or
Variable
Angle
TCUL tap position (primary
winding) or phase angle position
T6. Variable V Tap or Variable Angle
shall be at or within Max VAr Tap
and Min VAr Tap for Transformers
that are in-service.
Min VAr Tap ≤
V Tap ≤ Max
VAr Tap
Step Size
TCUL (pu) or phase-shift (angle in
deg) step
T7. Step Size shall reflect the
capability of the transformer.
FROM Angle
Primary winding phase angle (deg)
TO Angle
Secondary winding phase angle
(deg)
Tertiary
Angle
Tertiary winding phase angle (deg)
G-Core Loss
Magnetizing conductance (pu)
B
Magnetizing
Magnetizing susceptance (pu)
Rating 1
Summer Normal Branch Rating
(MVA) (primary winding for
3-winding xfmr)
T8. Transformer rating required.
Rating MVA 1
>0
Rating 2
Summer Emergency Branch Rating
(MVA) (primary winding for
3-winding xfmr)
T9. Transformer rating required.
Rating MVA 2
>0
Rating 3
Winter Normal Branch Rating
(MVA) (primary winding for
3-winding xfmr)
Rating 4
Winter Emergency Branch Rating
(MVA) (primary winding for
3-winding xfmr)
Rating 5
Fall Normal Branch Rating (MVA)
(primary winding for 3-winding
xfmr)
Rating 6
Fall Emergency Branch Rating
(MVA) (primary winding for
3-winding xfmr)
Rating 7
Spring Normal Branch Rating
(MVA) (primary winding for
3-winding xfmr)
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Field
Description
Rating 8
Spring Emergency Branch Rating
(MVA) (primary winding for
3-winding xfmr)
TO Winding
Rating MVA
1
Ratings – secondary winding for
3-winding xfmr
TO Winding
Rating MVA
2
Ratings – secondary winding for
3-winding xfmr
TO Winding
Rating MVA
3
Ratings – secondary winding for
3-winding xfmr
Tert Wind.
Rating MVA
1
Ratings – tertiary winding for
3-winding xfmr
Tert Wind.
Rating MVA
2
Ratings – tertiary winding for
3-winding xfmr
Tert Wind.
Rating MVA
3
Ratings – tertiary winding for
3-winding xfmr
FROM Loss
Assign
Loss assignment factor (primary
winding for 3-winding xfmr) (pu)
TO Loss
Assign
Loss assignment factor - secondary
winding for 3-winding xfmr (pu)
Tert Loss
Assign
Loss assignment factor – tertiary
winding for 3-winding xfmr (pu)
Max Var. Tap
Maximum TCUL ratio (pu or deg)
Min Var. Tap
Minimum TCUL ratio (pu or deg)
Max Cont V
or MW
Maximum voltage (power) at
controlled bus (pu or MW)
Min Cont V
or MW
Minimum voltage (power) at
controlled bus (pu or MW)
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Requirements
Measure
T10. Max Var. Tap shall be greater than
Min Var. Tap.
T11. Max Cont V shall be greater than
Min Cont V.
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Description
Ohms
Ohmic data flag
22
Requirements
Measure
 0 = impedances in pu
 1 = impedances in ohms
Owner
Owner Number (1 through 8)
T12. Owner Number shall be the
Transmission Owner for
transmission facility and Generator
Owner for generator facility.
T13. WECC staff shall assign Owner
Number to required entities.
Fixed Shunt Reactive Elements (MOD-011, R1.6)
General Requirements
1. Represent fixed shunt elements that are directly connected to a bus as bus shunts.
2. Represent fixed shunt elements that directly connect to and switch with a transmission line as line
shunts.
3. Fixed shunt reactive devices inside wind and solar projects must be modeled explicitly in power
flow.
Table 5: Data Requirements (Fixed Shunts)
Field
Description
Requirement
FROM Bus
Number
Number of the Bus to which the FROM end of the
transmission line on which the shunt is connected
for line shunts or number of the Bus at which
shunt is connected for bus shunts.
 See “Data Requirements (Buses)”
TO Bus Number
Number of the Bus to which the TO end of the
transmission line on which the shunt is connected
for line shunts or 0 for bus shunts.
 See “Data Requirements (Buses)”
Shunt ID
F1. Line shunt connected to the FROM
end of the transmission line shall
have Shunt ID starting with ‘F.’
F2. Line shunt connected to the TO
end of the transmission line shall
have Shunt ID starting with ‘T.’
Shunt identifier
 Two-character shunt identifier
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Field
Description
Requirement
Circuit ID
AC Transmission Line circuit identifier for line
shunts or blank for bus shunts
 Two-character circuit identifier
Section Number
Number of AC Transmission Line section to which
shunt is connected if line shunt or ‘0’ if bus shunt
Shunt Status
Shunt status
F3. Fixed shunts shall have the
anticipated status of the shunt in
the case.
 0 = out-of-service
 1 = in-service
Area
Area in which fixed shunt is located
F4. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated Area.
Zone
Zone in which fixed shunt is located
F5. Refer to “Appendix 2 – Area, Zone
and Bus Number Assignments” for
designated ranges of Zones used
by Area.
G
Actual shunt conductance (pu)
B
Actual shunt susceptance (pu)
Owner
Owner Number (1 – 4)
F6. Owner Number shall be the
Transmission Owner or Generator
Owner.
F7. WECC staff shall assign Owner
Number to required entities.
Controlled Shunt Reactive Devices (MOD-011, R1.6)
General Requirements
1. Controlled shunt reactive device models should be used to represent the following devices
explicitly in power flow:

Mechanically switched shunt capacitors and reactors;

Static VAR Compensators;

STATCOMs; and/or

Thyristor-switched shunt capacitors and reactors.
2. Controlled shunt reactive devices inside wind and solar projects must be modeled explicitly in
power flow.
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Table 6: Data Requirements (Controlled Shunts)
Field
Bus Number
Description
SVD ID
SVD identifier
 Two-character identifier
SVD Status
SVD status
 0 = out-of-service
 1 = in-service
SVD Control Type
Device type
 0 = Fixed
 1 = Discrete
 2 = Continuous
 3 = All or Nothing
 4 = Discrete control using Voltage Dead Band
 5=WECC SVC
 6=WECC STATCOM
 7=WECC TSC/TSR
Number of Bus regulated by this shunt
 See “Data Requirements (Buses)”
Regulated Bus
Requirement
Number of Bus at which device is connected
 See “Data Requirements (Buses)”
S1. Controlled shunts shall have
the anticipated status of the
shunt in the case.
S2. Regulation of a remote Bus that
does not represent actual
system operation shall be
avoided.
Area
Area in which Controlled Shunt is located
S3. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
Area.
Zone
Zone in which Controlled Shunt is located
S4. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
ranges of Zones used by Area.
G Actual
Actual shunt conductance (pu)
B Actual
Actual shunt susceptance (pu)
B Min
Minimum susceptance of continuous element (pu)
B Max
Maximum susceptance of continuous element
(pu)
Voltage Dead
Band
Voltage control bandwidth divided by two (pu)
(types 3 and 4)
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S5. Voltage Dead Band shall
prevent regulated voltage from
exceeding the Voltage Dead
Band with a single Controlled
Shunt step.
S6. The minimum dead band shall
be 0.02.
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Field
B Step
Description
Requirement
Susceptance of each switched element in nth
stage (pu) (types 1-4, 7)
S7. Step size shall reflect the
capability of the controlled
shunt.
No. of Steps
Number of equal admittance steps in nth
switched stage (types 1-4, 7)
S8. Number of steps shall reflect
the capability of the controlled
shunt.
B Min
Minimum total susceptance for device (pu)
B Max
Maximum total susceptance for device (pu)
Maximum current for type 6 (pu)
XC
Compensating (slope) reactance (pu) (types 5, 6,
7)
B Min SH
Minimum B for switching shunts (pu) (types 5, 6,
7)
B Max SH
Maximum B for switching shunts (pu) (types 5, 6,
7)
STSB
Slow reset control on/off status (pu) (types 5, 6, 7)
B Min SB
Minimum B for slow reset (pu) (pu) (types 5, 7)
B Max SB
Maximum B for slow reset (pu) (pu) (types 5, 7)
VRFMIN
Minimum Voltage reference for slow reset (pu)
(types 5, 6, 7)
Minimum Voltage reference for types 3 and 4 if
Voltage Dead Band <= 0
VRFMAX
Maximum Voltage reference for slow reset (pu)
(types 5, 6, 7)
Maximum Voltage reference for types 3 and 4 if
Voltage Dead Band <= 0
dVdB
System dV/dB for slow reset (pu) (types 5, 6,
and 7)
Ni
Number of steps in shunt
Owner
Owner Number (1 through 4)
S9. Owner Number shall be the
Transmission Owner or
Generator Owner.
S10. WECC staff shall assign Owner
Number to required entities.
Loads (MOD-011, R1.1)
General Requirements
1. Real and reactive power for each load shall be provided.
2. Motors 10 MVA or larger shall be modeled as machines (see “General Requirements:).”
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3. Station service at modeled generation facilities with station service load greater than or equal to 1
MW shall be modeled explicitly. As noted in the table below, load modeling generator station
service shall have Load ID set to ‘SS.’
4. A Long ID shall be provided for each load in accordance with the WECC MVWG Load Long ID
Instructions (LID_Instructions), either within the case data provided, or in a separate spreadsheet
file. See Dynamic section 6B Load Characteristics. There is a separate Long ID for Station Service or
generator Auxiliary loads.
5. Industrial loads and embedded generation shall be modeled on the low side of the transformer, as
shown in the figure below.
115-kV
WRONG! Industrial load is netted
with embedded generation
10 MW
115-kV
G
90 MW
WRONG! Industrial load and
embedded generation are
connected to high voltage bus
100 MW
115-kV
13.8-kV
G
90 MW
100 MW
RIGHT! Industrial load and
embedded generation are
connected to low voltage bus
Table 7: Data Requirements (Loads)
Field
Description
Requirement
Bus
Number of Bus at which load is connected
Number
 See “Data Requirements (Buses)”
Load ID
Two-character identifier
L1. Load modeling generator
station service shall have Load
ID set to ‘SS.’
L2. Loads at the same Bus shall
have unique Load ID.
Load Status
 0 = load out-of-service
L3. Load shall have the
anticipated status of the load
in the case.
 1 = load in-service
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Field
Description
Requirement
Non-Conforming
Flag
 0 = load will change with scaling
L4. Non-conforming Flag shall be
set to ‘1’ for loads which
should not be changed in load
scaling operations of power
flow software.
Area
Load Area in which located
L5. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
Area.
Zone
Load Zone in which located
L6. Refer to “Appendix 2 – Area,
Zone and Bus Number
Assignments” for designated
ranges of Zones used by Area.
Const MVA P
Constant MVA Real Power load
Const MVA Q
Constant MVA reactive power load
Const CUR P
Constant current Real Power load
L7. Const CUR P shall not be used.
Const CUR Q
Constant current reactive power load
L8. Const CUR Q shall not be
used.
Const Y P
Constant admittance Real Power load
L9. Const Y P shall not be used.
Const Y Q
Constant admittance reactive power load
L10. Const Y Q shall not be used.
Owner
Owner Number
L11. Owner Number shall be the
Transmission Owner,
Generator Owner, or
Distribution Service Provider.
 1 = load does not change with scaling
L12. WECC staff shall assign Owner
Number to required entities.
Long ID
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L13. Seven-character identifiers of
the climate zone and load
type – the first three
characters represent the
climate zone, underscore, and
three characters representing
the substation/feeder type.
Details are included in the
LID_Instructions and
Composite Load Model
Implementation documents.
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DC Transmission Lines (MOD-011, R1.4)
General Requirements
1. Include (at a minimum) the following DC Transmission Line (overhead and underground)
requirements: line parameters, Normal and Emergency Ratings, control parameters, rectifier data,
and inverter data.
2. Megawatt set-point of converter data shall be equal to or less than the DC Transmission Line
Rating.
Table 8: Data Requirements (DC Transmission)
Field
Description
Requirement
Measure
ifrom
DC ‘FROM’ bus number
ito
DC ‘TO’ bus number
ck[2]
DC line identifier
projid
Project Identifier
st
DC line status
dcsys
DC system number
area
Area number
zone
Zone number
r
DC line resistance
ohms
l
DC line inductance
henries
c
DC line capacitance
microfarad
rate[8]
DC current ratings
amps
aloss
DC line loss assignment factor
per unit
nown[8]
Owner Number
Area Interchange Schedules (MOD-011, R1.7)
General Requirements
1. Area Interchange schedules shall be coordinated between Areas to meet the objectives of the data
request letter.
2. The sum of net Area Interchange Schedules shall be equal to zero.
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3. WECC staff shall set the Real Power Net Interchange Tolerance equal to 1.0 MW for each Area.
Data Requirements (Area Interchange)
1. Zones – Zone Names and Zone Numbers shall be maintained in the BCCS. Zone assignments to the
applicable entities (see “Appendix 2 – Area, Zone and Bus Number Assignments.”)
2. WECC staff shall identify paths (as listed in the WECC Path Rating Catalog) in the BCCS under the
Interface Data section. The Interface Number shall match the WECC path number. Rating 1 shall be
used for the Path Transfer Limit for prevailing flow direction and Rating 2 shall be used for the
secondary flow direction Path Transfer Limit.
3. WECC path element information shall be maintained in the BCCS. Area Coordinators shall provide
updates to WECC staff as changes are made or as facilities are placed in-service.
4. Facility owners of DC buses, lines, and converters that are part of any area tie line shall provide the
steady-state data to be maintained in the BCCS.
5. Transformer Impedance Correction Table – Impedance correction parameters to be used for TCUL
transformers and phase-shifting transformers shall be maintained in the BCCS.
6. Owner Data – A list of Owner Numbers, names, and four-character abbreviations shall be
maintained in the BCCS.
7. Transaction Data – There must be a transaction for any connection between Areas. Staff manages
this data in the BCCS on a case-by-case basis.
VI. Dynamic Data Requirements
The WECC staff, in concert with the SRWG, MVWG and other entities as appropriate, is responsible for
managing the collection of the dynamic data required to comply with applicable NERC Standards and
Measurements.
To provide consistency in data submittals and help avoid potential solution problems, the guidelines
below shall be followed to the maximum extent possible. However, WECC recognizes deviations from
the guidelines may occasionally be needed. For these situations, submitters are requested to provide
the SRWG and MVWG with the rationale for exceptions. In all cases, dynamic data must be consistent
with steady-state data provided for each WECC Base Case. The facility owners are responsible for
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providing data for their solely- or jointly-owned facilities in the format specified and for the accuracy of
these data, either directly or through a Data Representative, at the option of the owner.
Approved dynamic models conform to the WECC Dynamic Modeling Procedure. All dynamic models
contained in the MDF shall be those approved by MVWG. If the model you want to use is not on the
approved list, you must go through MVWG and follow the WECC Dynamic Modeling Procedure.
The following approach to dynamic data shall apply Interconnection-wide:

Generators and other dynamic devices shall be represented with approved dynamic data as
recommended by the MVWG to represent the designated dynamic equipment modeled in
WECC Base Cases. The approved models can be found within the Approved Dynamic Model
Library
o
When new models have been added to or obsolete models have been removed from the
Approved Dynamic Model Library, TSS and SRWG will determine an appropriate
implementation schedule and scope for submitting the necessary data required by the
newly approved models.

Estimated or typical manufacturer’s dynamic data based on facilities of similar design and
characteristics may be used to represent planned generators and other dynamic devices if
specific design data cannot be obtained. MVWG maintains the Typical Machine Data document.
Specific dynamic design data shall be submitted according to the WECC Steady-State and
Dynamic Data Criterion

Where there is a difference between the requirements of this document and the WECC
Generating Unit Model Validation Policy, the WECC Generating Unit Model Validation Policy
shall preside.

Typical dynamics studies are up to 60 seconds from the initiating event. All models, on the
Approved Dynamic Model Library list, that can respond within that time frame shall be
submitted.
Generation Requirements
1. Design data for new or refurbished excitation systems (for synchronous generators and
synchronous condensers) shall be provided at least three months prior to the in-service date. If
design data is unavailable from the manufacturer, estimated or typical manufacturer’s data, based
on excitation systems of similar design and characteristics, shall be provided three months prior to
the in-service date.
2. Dynamic data for generators, synchronous condensers, excitation systems, voltage regulators,
turbine governor systems, power system stabilizers, and other associated generation equipment
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shall be derived from test results obtained by adhering to the WECC Generating Unit Model
Validation Policy for each unit represented in WECC Base Cases according to thresholds as specified
in WECC Steady-State and Dynamic Data Criterion This includes, as appropriate to the model, items
such as inertia constant, damping coefficient, saturation parameters, and direct and quadrature
axis reactances and time constants.
3. Generator Owners shall submit power plant data in accordance to the size thresholds as described
in the WECC Steady-State and Dynamic Data Criterion.
4. Netting of planned generators represented in WECC Base Cases shall conform to the threshold
requirements of the WECC Steady-State and Dynamic Data Criterion.
5. The MWCAP parameter in the dynamic turbine-governor model shall be greater than or equal to
the Pmax parameter of the generator steady-state model to avoid governor initialization problems.
6. Power System Stabilizer (PSS) Dynamic data shall be submitted for all generators that have active
PSS. See the WECC Policy Statement on Power System Stabilizers document.
7. Existing generators shall follow the WECC Generating Unit Model Validation Policy.
Load Characteristics
The goal of this section is to model effects of voltage and frequency on load as accurately as possible.
1. Keep dynamic load data consistent with reported steady-state data supplied.
2. Modeling voltage and frequency characteristics explicitly for each individual load, if possible.
However, use default zone or area records for buses not explicitly defined.
3. For loads less than 5 MW, Area Coordinators will work with WECC staff to establish a default load
representation record for each area to represent loads not modeled with the CMPLDW model. This
is to avoid the load representation defaulting to constant power (PSLF default). If actual dynamic
load characteristics are not available, load should be modeled as constant current P, and constant
impedance Q. Bus specific exceptions to the default load representation must be submitted to
WECC staff for inclusion in the MDF.
Underfrequency Load Shedding (UFLS)
1. Include Underfrequency Load Shedding records for all loads that have underfrequency relays on
the interconnected system.
2. Ensure the pickup frequency of each stage is lower than that of the previous stage. UFLS must
comply with WECC-coordinated off-nominal requirements as specified in the WECC Off-Nominal
Frequency Load Shedding Plan document.
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3. Include pertinent load data in the MDF. All Underfrequency Load-Shedding data in the MDF must
match bus, load, and/or branch identifiers in the operating cases. For this data category, the MDF
data is not a master database because it does not apply to planning cases. If data is to be included
in the planning cases, the data is to be submitted with the case development and identified as
planning data.
4. UFLS models provided for each base case must correspond to UFLS information provided to WECC
Underfrequency Load-Shedding Review Group in accordance with WECC Underfrequency Load
Shedding Criterion.
Undervoltage Load Shedding (UVLS)
1. Include undervoltage load-shedding records for all loads that have undervoltage relays on the
interconnected system.
2. Coordinate the pick-up and time-delay setting for each stage with the previous stage.
3. Include pertinent load data in the MDF. All undervoltage load-shedding data in the MDF must
match bus, load, and/or branch identifiers in the operating cases. For this data category, the MDF
data is not a master database because it does not apply to planning cases. If data is to be included
in the planning cases, the data is to be submitted with the case development and identified as
planning data.
Relays
Include relay models as approved for use by the SRWG per the time line and scope it establishes for
primary relays. Data submitters are also strongly encouraged to submit all relevant backup relay
modeling data.
Back-to-Back DC Ties
Netting is allowed for back-to-back DC ties. Represent back-to-back DC ties as generation in the
power flow, but netted in dynamic data. The record should include an ID designation of ‘DC’ on the
generator record.
DC Lines, SVC, and D-VAR systems
1. Device specific dynamic data for dynamic devices shall be modeled, including but not limited to
static VAR compensators and controllers, high-voltage direct-current systems, flexible AC
transmission systems, and automatically switched shunt and series capacitors or reactors.
2. Model, to the maximum extent possible, DC lines and SVC systems to accurately reflect actual
system performance.
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3. Coordinate DC bus numbering with WECC staff prior to model submission.
VII.
Short Circuit Data
MOD-032-1 requires that short circuit data should be shared openly between applicable NERC
functional entities. This data should be provided upon request by applicable NERC functional entities in
the data owners preferred software format.
VIII. Contingency and Remedial Action Scheme Data
NERC and FERC are suggesting that contingency and Remedial Action Scheme (RAS) data should be
shared openly between applicable NERC functional entities.
The following approach should be taken when providing contingency and RAS data:
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All models should be provided upon request by applicable NERC functional entities in the
providers preferred format until the WECC common format is available in the providers
preferred software.

Provide all contingencies used for internal TPL studies.

RAS models should be provided if the affected elements are modeled in the case.
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Disclaimer
WECC receives data used in its analyses from a wide variety of sources. WECC strives to source its data
from reliable entities and undertakes reasonable efforts to validate the accuracy of the data used.
WECC believes the data contained herein and used in its analyses is accurate and reliable. However,
WECC disclaims any and all representations, guarantees, warranties, and liability for the information
contained herein and any use thereof. Persons who use and rely on the information contained herein
do so at their own risk.
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Appendix 1 – Late Data Procedure
The objective of the Late Data Procedure is to preserve the original schedule for the development of
base cases in accordance with each year's Data Bank Compilation Schedule, and the Case Description
sheet in the data request letter for each case. The Late Data Procedure describes Area Coordinator and
staff data submittal responsibilities as well as actions to be taken for actual delays or anticipated delays
in the submittal of data or for the submittal of unusable data. This procedure does not take effect until
one of the following occurs:

A data submittal date has been missed; or

There is sufficient reason to believe that a submittal date will be missed; or

It is determined that the submitted data is not usable.
Success of the case development program depends on timely and accurate data submittal, review, and
support of the development of each base case. An Area Coordinator or Member System not meeting a
scheduled response date listed in the Data Bank Compilation Schedule section of the PCC Handbook
with a usable response could result in a delay in the case development schedule if left uncorrected.
Examples of unusable data:

Data from two neighboring Area Coordinators with inter-area schedules that do not match; and

Data with such significant problems that it cannot be used for the comment phase
development process which; therefore, delays the progress of the case development.
Any unusable data received by the Area Coordinator or WECC staff must be corrected by the
responsible party so as to not further impair the schedule or it will be rectified in accordance with this
Late Data Procedure, as will any late data or anticipated late data.
Area Coordinator and Staff Responsibilities
It is the responsibility of every “data owner” to submit timely and accurate data in accordance with the
Data Bank Compilation Schedule and the Case Description sheet in the data request letter. However, if
in the judgment of the Area Coordinator it appears that the original schedule will be impaired due to
late data submittal or submittal of unusable data,1 it will be the responsibility of the Area Coordinator
to provide the data for the Member System regarding the case in question. A schedule can be impaired
1 Unusable data is defined as: data that has been submitted for use in a power flow/dynamic study case that produces unreasonable
power flow/initialization results as may be determined by unreasonable solution results, significant run-time data errors being
reported, or a diverging power flow solution and is data that clearly does not meet the objectives of the case for which it is being
submitted.
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either by data being submitted after the scheduled due date or by the submission of unusable data,
even if it is submitted on time.
If, in the judgment of WECC staff, it appears that the schedule will be impaired due to lack of usable
data response by the Area Coordinator, it will be the responsibility of WECC staff to provide the data
for the case in question.
Actions to Take
There are two actions specified by this procedure in the event that the Area Coordinator or WECC staff
has to exercise its late data responsibilities for a delinquent entity. The first is the action of assuming
the responsibility for submitting the data and the second is the notification of such action. If the staff
or the Area Coordinator takes over the responsibility for the submittal of data for the delinquent
entity, the data to be submitted should always be the best data available in the judgment of the
person submitting the data. The data should be submitted in such a way that the original schedule is
maintained or not further impaired.
At the time the Area Coordinator takes over data submittal responsibility for the Member System:
1. The Area Coordinator will immediately notify the staff.
2. The staff will then notify the WECC Member Representative of the Member System and copy the
notification of the action taken to:
a. PCC and TSS representatives of the Member System; and
b. All Area Coordinators and Sub-Coordinators directly involved.
3. When the case involved is an operating case for OTC studies, the staff will send a notification letter
to:
a. The PCC, TSS and SRWG chairs;
b. All of TSS and SRWG; and
c. The Operating Committee (OC) and the Operating Transfer Capability Policy Group
Study Group (OTCPGSG).
The notification will consist of the nature and extent and reasons of the action taken. The staff will take
the same notification action if they also must exercise their late data responsibility in the interest of an
Area Coordinator. Those who consistently abuse the base-case development process by submitting late
or unusable data may be significantly compromising the reliability of the Western Interconnection
transmission system, which may eventually become a NERC compliance issue.
Backfitting of Late Data
The Late Data Procedure allows for an Area Coordinator or the staff to take over data submittal
responsibilities for a delinquent entity in the event that entity is unable to submit usable data in
accordance with the defined schedule. If the delinquent entity's data should subsequently become
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available, the data shall be submitted to the appropriate Area Coordinator or to the staff to partially or
fully replace that which was previously submitted. However, the staff may refuse to accept this backfit
data if, in its judgment, the backfit data is no better than the data already in the case or if there would
be unacceptable impairment of the schedule by accepting the backfit data.
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Appendix 2 – Area, Zone and Bus Number Assignments
Southwest Region
Area Number Range
Zone Number Range
10 – 18
100 – 199, 1000 – 1999
Bus Number Range
10,000 – 19,999
100,000 – 199,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
10
100-109
1000 - 1099
New Mexico
PNM
10,000 – 10,999
100,000 – 109,999
120-139
1200 - 1399
New Mexico
TSGT
12,000 – 12,999
120,000 – 129,999
LAC, NAPI, TNP
13,000 – 13,999
130,000 – 139,999
11
110 – 119
1100 - 1199
El Paso
EPE
11,000 – 11,999
110,000 – 119,999
14
140-149
1400 - 1499
Arizona
APS
14,000 – 14,999
84,000 – 85,999
140,000 – 149,999
150-159
1500-1599
SRP, APA
15,000 – 15,999
150,000 – 159,999
160-169
1600 - 1699
TEP, UES
16,000 – 16,999
160,000 – 169,999
170-179
1700 - 1799
AEPC, Others
17,000 – 17,999
170,000 – 179,999
190 – 199
1900 - 1999
WALC
19,000 – 19,999
190,000 – 199,999
NEVP
18,000 – 18,899
180,000 – 188,999
VEA
18,900 – 18,999
189,000 – 189,999
18
180 – 188
1800 - 1889
Nevada
189
1899
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Southern California Region
Area Number Range
Zone Number Range
20 – 29
200 – 299
2000 – 2999
Bus Number Range
20,000 – 29,999
94,000 – 95,999
200,000 – 299,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
20
200 – 209
2000 - 2099
Mexico – CFE
CFE
20,000 – 20,999
200,000 – 209,999
21
210 – 219
2100 – 2199
Imperial, CA
IID
21,000 – 21,999
210,000 – 219,999
22
220 – 239
2200 – 2399
San Diego
SDGE
22,000 – 22,999
220,000 – 229,999
Others
23,000 – 23,999
230,000 – 239,999
SCE
24,000 – 24,999
240,000 – 249,999
24
240 – 259
2400 – 2599
So Calif
940 – 959
9400 – 9599
26
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260 – 299
2600 – 2999
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94,000 – 95,999
29,000 – 29,999
290,000 – 299,999
LADWP
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CDWR, MWD,
Others
25,000 – 25,999
250,000 – 259,999
LDWP
26,000 – 26,999
260,000 – 269,999
BURB, GLEN
27,000 – 27,999
270,000 – 279,999
Others
28,000 – 28,999
280,000 – 289,999
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Northern California Region
Area Number Range
Zone Number Range
30 – 39
300 – 399
3000 – 3999
Bus Number Range
30,000 – 39,999
300,000 – 399,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
30
300 – 399
3000 – 3999
PG and E
PG&E
30,000 – 36,999
300,000 – 369,999
SMUD
37,000 – 37,499
370,000 – 374,999
SNR
37,500 – 37,899
375,000 – 378,999
REU
37,900 – 37,999
379,000 – 379,999
NCPA
38,000 – 38,199
380,000 – 381,999
MID
38,200 – 38,399
382,000 – 383,999
TID
38,400 – 38,599
384,000 – 385,999
CDWR
38,600 – 38,899
386,000 – 388,999
Others
38,900 – 39,999
389,000 – 399,999
WAPA
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Northwest Region
Area Number Range
Zone Number Range
40 – 49
400 – 499
4000 – 4999
Bus Number Range
40,000 – 49,999
90,000 – 90,999
400,000 – 499,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
40
400 – 499
4000 – 4999
Northwest
BPA, other Federal,
WPPSS, Detailed
Federal hydro
40,000 – 41,999
44,000 – 44,499
400,000 – 419,999
440,000 – 444,999
PSE
42,000 – 42,999
420,000 – 429,999
PGE
43,000 – 43,999
430,000 – 439,999
Not used
44,000 – 44,499
440,000 – 444,999
PACW
44,500 – 45,599
445,000 – 455,999
SNPD
45,600 – 45,999
456,000 – 459,999
GCPD
46,000 – 46,199
460,000 – 461,999
EWEB
46,200 – 46,399
462,000 – 463,999
SCL
46,400 – 46,599
464,000 – 465,999
TPWR
46,600 – 46,799
46,900 – 46,999
466,000 – 467,999
469,000 – 469,999
CHPD
46,800 – 46,899
468,000 – 468,999
Others – Public
47,000 – 47,499
470,000 – 474,999
Others – Private or
IOU
47,500 – 47,999
475,000 – 479,999
AVA
48,000 – 49,999
480,000 – 499,999
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Canadian Region
Area Number Range
Zone Number Range
50 – 59
500 – 599
5000 – 5999
Bus Number Range
50,000 – 59,999
80,000 – 81,999
500,000 – 599,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
50
500 – 519
5000 – 5199
BC Hydro
BCHA
50,000 – 51,999
500,000 – 519,999
80,000 – 81,999
52
520 – 539
520 – 5399
Fortis BC
FBC
52,000 – 53,999
520,000 – 539,999
54
540 – 599
5400 – 5999
Alberta
AESO
54,000 – 59,999
540,000 – 599,999
Central Region
Area Number Range
Zone Number Range
60 – 69
600 – 699
6000 – 6999
Bus Number Range
60,000 – 69,999
600,000 – 699,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
60
600 – 619
6000 – 6199
Idaho
IPC
60,000 – 60,999
600,000 – 609,999
BPA, Others
61,000 – 61,999
610,000 – 619,999
62
620 – 629
6200 – 6299
Montana
NWMT
62,000 – 62,999
620,000 – 629,999
63
630 – 639
6300 – 6399
WAPA UGP
WAUW
63,000 – 63,999
630,000 – 639,999
64
640 – 649
6400 – 6499
Sierra
SPP
64,000 – 64,999
640,000 – 649,999
65
650 – 699
6500 - 6999
Pace
PACE-UT, WY, ID
65,000 – 69,999
650,000 – 699,999
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Eastern Region
Area Number Range
Zone Number Range
70 – 79
700 – 799
Bus Number Range
70,000 – 79,999
700,000 – 799,999
Member System
Bus Range
Area No.
Zone Range
Area Name
Member System
70
700 – 729
7000 – 7299
PSColorado
PSC
70,000 – 70,999
700,000 – 709,999
WPE
71,000 – 71,999
710,000 – 719,999
TSGT
72,000 – 72,999
720,000 – 729,999
WALM
73,000 – 73,999
730,000 – 739,999
BHPL
74,000 – 74,999
740,000 – 749,999
PRPA
75,000 – 75,999
750,000 – 759,999
BEPC
76,000 – 76,999
760,000 – 769,999
WAUC
79,000 – 79,999
790,000 – 799,999
73
730 – 799
7300 – 7999
WAPA R.M.
Area Number Range
Zone Number Range
Not Applicable
Not Applicable
Bus Number Range
97,000 – 99,999
897,000 – 899,999
997,000 – 999,999
Bus Number Range
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1-9,999
90,000 – 91,999
(Temporary)
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Revision History
Version
Version Date
June 26, 2012
Editor(s)
Revision Description
Mark Mallard
Gordon Comegys
Doug Tucker
Added Turbine Type field for Generators
Expanded bus number ranges for Areas
Added dynamic data submittal requirement to
include all devices that could respond within 60
seconds if an approved model exists
October 12, 2012
Doug Tucker
Gordon Comegys
Don Streebel


Added language for sub-100-kV elements
Fixed minor changes in text
July 18, 2014
Jonathan Young







Accommodate BES Definition
Reword UVLS sections
Added Short Circuit Data info
Added Contingency and Remedial Action Scheme
Data
Bus number ranges slightly changed
Few member Acronyms changed
Fixed minor changes in text
Doug Tucker
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

BCCS
BCCS Version
Jonathan Young

Incorporated BCCS methodologies
December 12,
2014 (SRWG
Approval)
Jonathan Young
BCCS-4
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Added four digit zone number ranges
WECC Technical Writer edits and formatting
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